i cant remove the lower part of the exhaust where the flexi pipe is situated. so far ive managed to shear 2 bolts, which actually helped a little, but i fear if i attempt to loosen the others it may cause more problems and i wont be able to remove the manifold.
is there any advice that anyone could give me?

the bolts that connect the manifold to the part with the flex pipe?

soak them in penetrating oil and then use an impact gun to remove those.

yeh thats them. this part in the picture

i couldn't understand why there is a torx bit on the end of the thread as well as a nut.

because its a stud.